1. Field of the Invention
This invention relates to a shaft alignment method and apparatus, and more particularly, to method and apparatus for use in alignment of shafts along a common center line, e.g., where the shafts are associated with two pieces of rotating equipment adapted to be coupled together in driving relationship with one another.
2. Discussion of the Prior Art
Generally, it is necessary to shut down the operation of axially coupled rotating items of equipment in order to align the shafts of the equipment items precisely along a common axis. This is disadvantageous because the alignment process is time-consuming and requires a long equipment shut-down time. Further, when the shafts are cold, their physical shape differs from when they are at operating temperatures, thus making it difficult to effect a proper alignment with the shafts not in operation which will yield a correct alignment of the shafts during operation thereof.
Although it is known to use a visual sighting technigue directly on the shafts themselves to effect alignment while one of the equipment items is kept running, e.g., by placing bench marks on both of the items of equipment and visually sighting down the shafts to determine if they are aligned, this technique does not provide high accuracy, and hence is unsuitable for systems requiring high precision alignment.